1. Field of the Invention
The present invention relates to an electromechanical actuator for an internal combustion engine provided with a conditioning circuit.
2. Description of the Related Art
An internal combustion engine supercharged by a turbocharger supercharging system typically includes a number of cylinders, each connected to an intake manifold and to an exhaust manifold. The intake manifold receives a gas mixture comprising both exhaust gases and fresh air, i.e. air coming from the outside through an intake pipe, which is regulated by a throttle valve. The exhaust manifold is connected to an exhaust pipe, which feeds the exhaust gases produced by the combustion to an exhaust system, which releases the gases produced by the combustion into the atmosphere and normally comprises at least one catalytic converter (if necessary, provided with a diesel particulate filter) and at least one silencer arranged downstream of the catalytic converter.
The internal combustion engine supercharging system comprises a turbocharger provided with a turbine, which is arranged along the exhaust pipe so as to rotate at a high speed due to the action of the exhaust gases expelled from the cylinders, and a supercharger, which is arranged along the intake pipe and is mechanically connected to the turbine so as to be caused to rotate by the turbine itself in order to increase the pressure of the air present in the feeding pipe.
The internal combustion engine comprises, furthermore, a high-pressure exhaust gas recirculation circuit and a low-pressure exhaust gas recirculation EGR circuit, along which EGR valves are arranged, which are designed to adjust the flow rate of the exhaust gases. Furthermore, there are provided a plurality of kinematic mechanisms, which are used to move devices such as the EGR valves, which are designed to adjust the flow rate of the exhaust gases, and/or the blades of the turbocharger, in case of a variable-geometry turbocharger.
Both the throttle valve and the aforementioned devices comprise electromechanical controlling actuators to adjust the position between an opening position and a closing position, and vice versa. Electromechanical actuators typically comprise an electric motor and a gear drive, which transmits the motion from the electric motor to a user interface.
In the greatest part of the electromechanical actuators available on the market, the entire holding body is made of a metal material, preferably aluminium, and is a one-piece body (i.e. it is made of one single piece without gaps).
As these electromechanical actuators are requested to operate in environments that get hotter and hotter, the need is felt to be able to condition them, so as to allow them to remain efficient in case of ageing and in case of great electromechanical stresses.